1. Field of the Invention
The present invention generally relates to wireless telecommunications, and more specifically, relates to a system and method for resolving media stream conflicts in communications among multiple communicating devices on a wireless network.
2. Description of the Related Art
Technology advancement has made mobile telephones or wireless communications devices inexpensive, and accordingly, ubiquitous. As wireless telecommunication devices are manufactured with greater processing ability and storage, they also become more versatile and incorporate many features including direct radio communication capability between two or a group of individual handsets. This direct radio communication capability is commonly known as the push-to-talk (PTT) or “walkie-talkie” feature that allows a user with one handset to communicate with the device of a predefined set of members of a group without dialing a destination telephone number.
In one version of a PTT system, a wireless telecommunication device, such as a handset, uses one single frequency for both upward and downward communications with a remote server, while in a normal wireless communication a wireless telephone uses two frequencies for communicating with the server, one for outgoing and one for incoming communications. The PTT system requires the person who is speaking to press a button while talking and then release it when done. Any listener in the group can then press their button to respond. In this manner, the system determines which direction the signal travels. In a typical configuration, when a user makes a call to a receiving party or a group of receiving parties using the PTT system, the user's handset first makes a request to a remote server. The remote server verifies that no other party is using the communication channel and the channel is available then assigns the channel to the user. The user's message is received by the server and the server sends the message for each and every receiving party. After the message is transmitted to every receiving party, the channel is released and ready for use by other parties.
The message is digitized (packetized) and sent as data through a series of sequential data packets according to a predefined protocol. The data packets are received at the user's communication device, where the data are retrieved, and assembled back into an audio stream. The reconstructed audio stream is then played to the user.
However, because of the data packets are transmitted over the air, the transmission and reception may not be very reliable. Sometime, the data packets are lost because of interference or weakness of signals. When one or two data packets are lost during the transmission, the loss may affect the quality of the reconstructed audio stream minimally, and is generally unnoticeable by the listener. On the other hand, if a larger number of data packets are lost during the transmission, it becomes difficult for the user device to reconstruct the audio stream and the quality of the reconstructed audio stream suffers.
In a related situation, when the lost data packets are from two distinct audio streams, it becomes almost impossible for the user device to reconstruct the audio streams. The user device often is not capable of deciding whether a received data packet belongs to a previous audio stream or to a new audio stream. When the user device constructs the audio stream and attaches a data packet of a new audio stream to an existing audio stream, it can result in part of the existing audio stream being overwritten or insertion of an artificial gap between the two spurts (“talking”).
Therefore, it is desirous to have an apparatus and method that enables a wireless device to reconstruct audio streams which may have one or more packets dropped, and it is to such an apparatus and method the present invention is primarily directed.